An electric vehicle generally includes an electric motor and a high-voltage storage battery. The high-voltage storage battery has a state of charge (SOC) and provides electric power to the electric motor to drive the vehicle. The SOC of the battery decreases when the battery provides electric power to drive the vehicle.
When the SOC of the battery decreases during a drive cycle, it may be desirable to capture the kinetic energy of the vehicle and convert the kinetic energy to electric energy to recharge the battery, such as during vehicle braking. However, the battery is unable to store the kinetic energy of the vehicle if the battery is at full capacity. For example, the battery may have a full capacity at a 100% charge level and be unable to store braking energy during a drive cycle that starts with the vehicle atop of a hill.
A power source external to the vehicle, such as a household power outlet on the GRID, may be used to charge or recharge the battery to the 100% charge level. However, it may be desirable or necessary to use the external power source to charge the battery to a target SOC below the 100% charge level prior to a drive cycle to allow the battery to recover braking energy during the drive cycle, such as when the vehicle start the drive cycle atop of the hill.